Typewriting machine



Oct-1, 1940. 'p w. F. HELMOND TYREWRITING MACHINE Filed May 8 1937 Patented Oct. 1, 1940 PATENT OFFlCE' TYPEWRITING MACHINE William F. Helmond, West Hartford, Conn., as-

signor to Underwood Elliott Fisher Company, New York, N. Y., a corporation of Delaware Application March 8, 1937, Serial No. 129,559

2 Claims.

This invention relates to typewriters and more particularly to stops for arresting the platencarriage, upon its return to the initial or banking position. The momentum produces a noisy and severe impact and. excessive rebound. Furthermore the p1aten-carriage is required to be brought to a final stop exactly at a predetermined letterspace position.

Both the carriage-stop and the frame-stop must be rigid and unyielding, andunder conditions of wear and use they must not change their relationship even in part.

The present improvements provide a carriagestop that checks rebound of the carriage and mutes the shock of impact.

A feature of the invention is a plurality of laminae, preferably on the engaging face of the stop and extending transversely to the direction of impact; the laminae may be resistant to internal distortion, both temporary and permanent; the laminae may all be fiat during impact; the laminae may all be locked together, and the locking device may be a pin or screw preferably passed through all the laminae at one side.

In a preferred form of the invention the laminae are identical in size and form and may be identical with that of the carriage-stop face itself, although they may vary in thickness and material; the lower portion of each lamina may have a central aperture through which passes a binding screw turned into the face of the carriage-stop. The laminae may be steel finished in white nickel.

In one form the laminae may be made of iron that is plated or coated with lead, cadmium or the like, or may be made of copper or some other rigid relatively inert, non-resilient or non-reso nant material.

In the preferred form of the invention the carriage-stop and the counter-stop engage each other only on the upper portion of the carriagestop face.

The principle of the invention is that the plates tend to counteract vibrations in the stop-face and therefore reduce the noise of impact and check the rebound of the carriage in the banking position. Experiments have shown that at least one intermediate plate is essential to any substantial choking of the vibrations set up in the banking stop by an impact against a counterstop. The plates are so held together as to be loosely packed at their impact receiving portions to form interstices for harboring cushioning air-films.

Other features and advantages will hereinafter appear.

In the accompanying drawing,

Figure 1 is a perspective View showing the invention applied to the carriage of an Underwood typewriter.

Figure 2 is a similar enlarged view of the banking stop.

Figure 3 is a front view of the banking stop on the carriage in operative engagement with the counterstop on the frame, a part sectioned.

Figure 4 is a similar enlarged View with the counterstop omitted.

Figure 5 is a top view, a part removed, showing a modified form of banking stop.

Figure 6 is a right side view with parts in section.

Figure 'I is a perspective view of the modification shown in Figure 5.

iii

Figure'B is an end view of a lead-coated plate forming one of the laminae of the stop.

Figure 9 is a cross-section of a lamina mad of fibrous or composition material. I

Figure 10 is a side view of a steel lamina having a white nickel finish.

A carriage of an Underwood typewriter has sides 2! which rotatably support the axle 22 of a cylindrical platen 23 on which a work-sheet 24 is fed from the table 25 and under the feed-rolls 23. At the left a usual line-space and carriagereturn lever 21 is pivoted on a screw 28 fastened on the carriage 20. A base 29 on the carriage 20 has front and rear grooves 30 which, joined with inner grooves 32 in the carriage base-support 33, confine antifriction balls 34 so that the carriage 2B is easily slidable both Ways. A spring drum 35 pivoted in the frame 33 at the left winds a spring 3'! which is tied to the carriage base 29 by a bracket 38. A rock-shaft 33 has end bearings in sides of the frame 36 and a rocking arm 40 has a horizontal pivotal connection 42 with the base-support 33 for shifting the platen 23 to the upper-case position shown in Figure 6 in a dot-and-dash line. A feed rack 43, mounted on the carriage-base 29, engages a toothed Wheel 44 fastened on the upper end of a shaft 45 which is rotatably supported in the base-support 33 and which turns with a toothed wheel 46 under the control of dogs 41 on an escapement 48 rockably mounted in the frame 36 by a link 49. The carriage 23 has a toothed cross-bar 50 and a reinforcing cross-piece 52.

A line-end stop 53 is adjustable on the crossbar 50 and settable by a spring-locked knob 54. A banking stop 55 is similarly adjustable and settable by the knob 54. A two-way counter-stop 56 is movable by the stop 53 to engage a wall 51 or by the banking stop to engage a wall 58, the walls 51 and 58 being formed by a cut in a rigid bracket 59 upright on the frame 36 and approximate a plane through the printing point.

The return of the carriage 20 to the banking position shown in Figure 3 is often at high speed so that the noise of impact and the rebound are both far greater than after a gentle return of the carriage 20. The present improvements include the placing of a combined muting device and rebound check on the working face 61 or the right side of the banking stop 55 which is cut back at the rear to leave a front vertical wall 66 rightangled to the face 61.

The banking stop 55 has a front upper flange and a lower flange 62 which form a slot 63 in which the bar 50 fits slidably. The front wall of the banking stop 55 has a vertical slot 64 to receive the lock-piece 65 which is normally yieldably held against a tooth of the rack cross-bar 50 by a coil spring 6| and pushed out of the rack by pushing down on the knob 54. This construction assures that the banking stop 55 is held firmly and rigidly in any set position along the cross-bar 50.

On the face 6! are laminae 10, Figure 4, which may be of sheet steel, and are packed against the face and one against the other, and held exactly by a screw 12 passed through holes 14 in the laminae 10 and into the banking stop 55. The pressure of the shoulder of the screw 72 on the 1aminae Hi forces them tightlyagainst one another at the bottom and so separates them slightly at the top. As shown in Figure 3 in the lower-case position the counterstop 56 engages the tops of the laminae 10, and therefore in most all of the impacts the blow on the laminae T0 is remote from the bound portion at the screw 12, the remote or loose parts of the laminae being more effective and having on their intermediate surfaces air-cushioning films. The laminae 10 are unyielding in the impact position, as shown in Figure 3, so that the stopping point of the carriage 20 is always true. In an Underwood typewriter having a counterstop 56 separate from the rigid stop wall 58 two laminae 10 are usually suflicient. One lamina 10 alone is not so effective, and therefore it is preferable to employ two or more. As shown in Figure 8 the coated surface 13 may be lead or cadmium, and as shown in Figure 9 a lamina 10 may be fibrous material, or Phenolite or the like, commercially available in sheets of uniform thickness, the white-nickel steel lamina 10 being preferable for the outer or contact lamina. Copper may also be used, or an alloy thereof, for a lamina. Inert rigid material may be used intermediately.

In a modification shown in Figures 5 and '7 the screw 12 has the inner face of its shoulder spaced from the outer face of the outer lamina 10 so that the laminae 10 are loosely held on the screw 12 by light springs 16 fastened on the end of the banking stop 55 by screws 11. A plate 18 may be fastened on the rear wall and top of stop 55 by screws 19, and hold the rear edges of the laminae by a forwardly and upwardly inclined wall. In lieu of the springs 16 a spring washer (not shown) may be placed under the shoulder of the screw 12. The modification, as shown in Figure 7, would be useful on typewriters where upper case is used in entire lines exclusively, the muting and rebound-checking effects being substantially uniform for the upper or lower case positions.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim:

1. In a typewriting machine having a carriage arresting counter-stop; a margin stop comprising a body having a back and also having a side surface, said side surface having a jog forming a face disposed toward said counter-stop, the jog extending from a vertical side thereof to said back of the body, a lamina-like plate structure, and, means retaining said plate structure in said jog to be struck facewise by said counter-stop, said retaining means including at least one clip attached to said body and overlapping the outer plate surface at said jog side to retain the plate structure facewise, a headed stud in said body passing loosely through a perforation provided in the plate structure, said retaining means also including an originally separate lip attached to said body to engage the edge of the plate structure at said back of the body, said jog side, stud and lip cooperating to engage edges of the plate structure to retain the plate structure against edgewise displacement, said retaining means clearing said counter-stop and being constructed to retain said plate structure substantially loosely facewise so that under impact with the counter-stop said plate structure becomes compacted against said face of the jog.

2. In a typewriting machine having a carriage arresting counter-stop; a margin stop comprising a body having a side surface, said side surface having a recess forming a face disposed toward said counter-stop, a lamina-like plate structure, and means retaining said plate structure in said recess to be struck facewise by said counter-stop, said retaining means including at least one clip attached'to said body to overlap in part the outer plate surface to retain the plate structure facewise, a retainer device attached to said body and engaging opposite upper and lower edges provided in the plate structure to retain the latter against vertical edgewise displacement, and also including a retainer device attached to the body and facing a vertical side of the recess to cooperate with said recess side to engage side edges of the plate structure to retain the latter against lateral displacement, said retaining means clearing said counter-stop and being constructed to retain said plate structure substantially loosely facewise so that under impact with the counterstop said plate structure becomes compacted against said face of the recess.

WILLIAM F. HELMOND. 

